4 yo DD is about average height (105 cm), but evidently has rather small feet (size 7). I bought her some new tights the other day that were the right leg length, but the heel of the foot part is halfway up her calf, and rubs with the back of her shoes. I tried washing them at 70 degrees in an attempt to shrink them a bit, but it didn't work 
Her old outgrown tights fit in the foot, but the crotch is halfway down her thighs - she reckons this is more comfortable than having the baggy feet, but she still spends her whole time hitching her tights up.
When she was tiny I used to buy her ones with no defined feet, but I can't seem to find that sort in cotton knit tights, in her size, only adult style denier tights, which I really don't want to put her in.
She absolutely refuses to wear leggings under dresses btw, before anyone suggests that.